A vegetarian is one who does not eat meat, fish and poultry. A vegan is a vegetarian who refrains from consuming all animal products including milk, cheese, eggs, wool, silk and leather.
The word 'vegetarian' is derived from the Latin word vegetus meaning 'whole, sound, fresh or lively', and its original meaning implies a balanced philosophical and moral sense of life apart from a diet of vegetables and fruits.

What are the reasons for being a Vegetarian?

Health reasons - there is evidence of a link between meat-eating and such killers as heart disease and cancer

Ecological reasons - concern about pollution and degradation of the environment

Religious reasons - all major religious scriptures condemn killing of any kind

Most vegetarian diets are generally lower than non-vegetarian diets in total fat, saturated fat and cholesterol. Studies have shown that vegetarians seem to have a lower risk of obesity, coronary heart disease (which causes heart attack), high blood pressure, diabetes mellitus and some forms of cancer.